This is pretty much common sense. Any OP jutsu in the manga/anime that have usually belonged to a single character in the anime/manga aren't allowed. To give you an idea, jutsu like the ones listed below (and more) aren't allowed.

Now, here, I am going to give you the restricted jutsu. Just because they are restricted, doesn't mean you can't use them, it just means they have certain restrictions on them to make them fair.

Shadow Clone jutsu: Can only have one out at a time. They cost 20CP and can use that 20cp to use jutsu. Once they are out of chakra or are hit in battle, they disappear and any remaining chakra is transferred back.

Five Elements Seal: Can only seal away elemental jutsu, victim can still use non-elemental jutsu. Lasts for 5 posts.

Important Body Points Disturbance: Lasts for 5 posts

Chidori: Can only move in a straight line. Gives tunnel vision to the user. Limited to only three people. Drawbacks only affect those without dojutsu. There are other circumstances in which the drawbacks wouldn't affect someone.